Genomic structure, chromosomal mapping, and muscle-specific expression of a PH domain-associated intronless gene, cded/lior

The aim of our study was to isolate novel gene(s) involved in cell differentiation and embryonic liver development. Mouse cded/lior was identified from subtraction hybridization of embryonic liver cDNA libraries as well as an adult mouse liver genomic DNA library. The full open reading frame of cded/lior encodes a 131-amino acid protein with 71.88% overall similarity to the PH domain of rat PLC-gamma1. A gapped search with the C-terminal region of CDED/LIOR revealed a 36-41% similarity to several proteins related to signal transduction and cell replication, such as ORC1 and KSR. Northern blot analysis of adult mouse tissues shows a strong 2.6-kb transcript restricted to heart and skeletal muscle. RT-PCR utilizing cded/lior-specific primers demonstrates cded/lior mRNAs in heart, brain, and liver tissue throughout mid-embryonic mouse gestation. cded/lior maps to the distal end of mouse Chromosome (Chr) 2. Analysis of the genomic structure for cded/lior demonstrated a single exon gene that is not an alternatively spliced isoform of PLC-gamma1. Analysis of the cded/lior promoter region revealed a high GC-content, high ratio of CpG/GpC, multiple GC-boxes, the lack of a TATA box, CTF/NFI element, and two MyoD-MCK binding sites. These characteristics are also found in several genes important in the regulation of cell growth or DNA synthesis, such as transforming growth factor-beta1, c-Ha-ras, nerve growth factor, epidermal growth factor receptor, and DNA polymerase beta. These results suggest that cded/lior is a mesoderm/muscle-specific transcript that may be involved in the mesodermal inductive and regulatory interactions required for liver formation and embryonic development.

Identification of a novel domain of HIV tat involved in monocyte chemotaxis

Human immunodeficiency virus (HIV) Tat is chemotactic for monocytes and dendritic cells, an activity that could play a key role in the expansion of HIV infection of accessory cells. To date, domains of Tat previously found to interact with cell surface molecules have shown only partial chemotactic activity toward monocytes. Using overlapping Tat peptides, we identify a novel region of Tat with a potent chemotactic activity for monocytes, reaching levels equal to Tat itself. This peptide also provokes monocyte polarization similar to Tat and is able to compete with Tat for induction of monocyte migration. Specific high affinity (kd = 3 x 10(-9) M) cell surface binding sites on monocyte cell surfaces for this region of Tat are demonstrated. These data indicate that the majority of Tat effects on monocytes are mediated by a novel region in the cysteine-rich and core domains. These domains are highly conserved among different HIV isolates, suggesting an important role in the establishment of HIV infection.

Identification of mouse itih-4 encoding a glycoprotein with two EF-hand motifs from early embryonic liver

An essential feature of cell differentiation is the specificity of signal transduction events from extracellular cues, which are considered to be conferred by scaffold, anchoring and adaptor proteins. Our aim was to identify important scaffolding proteins required for liver development. Utilizing subtraction hybridization of embryonic liver cDNA libraries, here we report the full length cDNA sequence for mouse itih-4 (Inter-alpha-trypsin inhibitor H4). Itih-4 encodes a 942 amino acid protein containing two EF-hand (helix-loop-helix) motifs with an unique short loop, with a potential calcium-binding function. Itih-4 is expressed as a strong 3.1-kb transcript in liver, to a lesser extent in lung and heart tissue. RT-PCR demonstrates itih-4 mRNAs abundantly in liver, less in heart and brain, during mid-embryonic gestation. These results suggest that itih-4 is a potential regulator for extracellular matrix proteins and plays a role during early embryonic liver development.

Identification of elf1, a beta-spectrin, in early mouse liver development

Beta-spectrins play essential roles in cell-cell interactions and in the maintenance of cell polarity. Our aim was to identify beta-spectrin genes important for the establishment of hepatocyte polarity and differentiation. Using subtractive screening of cDNA libraries from early embryonic mouse livers (post-coital days 10, 11, and 12), we have isolated elf1 (embryonic liver fodrin 1), a differentially expressed beta-spectrin or fodrin (betaSpIIsigmaI). Elf1 encodes a 220-amino acid protein with an NH2 terminal actin-binding domain. In situ hybridization studies demonstrate elf1 expression initially in day 10 embryonic heart tissue, then in day 11-11.5 hepatic tissue. These studies suggest that elf1 may play a role in the emergence of hepatocyte polarity during liver development.

Trinucleotide repeat expansion of spinocerebellar ataxia (SCA1) found in a Chinese family

OBJECTIVE

To investigate the gene mutation and the ratio of the spinocerebellar ataxia type 1 (SCA1) in Chinese patients with autosomal dominant spinocerebellar ataxia (ADSCA).

METHOD

The family material and DNA samples were collected from thirteen families with ADSCA. To determine the characteristics of the CAG trinucleotide repeats in SCA1 gene, the PCR products of the Rep1 and Rep2 primers were analyzed, and the bands with CAG repeat expansion were cloned by PCR2. 1 vector and sequenced.

RESULTS

One family was found to have an expanded CAG repeat in the 13 families with ADSCA. The clinically affected individual was heterozygous with one disease allele being 55 CAG repeats, whereas the mean size of the CAG repeats on 104 chromosomes generated from unrelated control Chinese individuals is 29.3 (ranging from 18 to 34).

CONCLUSIONS

The frequency of the SCA1 mutation is about 7% in the 13 Chinese families with ADSCA, suggesting that this type of genetic defect is not the main cause involved in the pathogenesis of ADSCA in China. Since the mutation has also been found in Caucasian, Japanese, Malaysian, and Bangladeshi kindreds, it is suggested that this genetic defect may well have multiple origins in different ethnic groups.

Praja1, a novel gene encoding a RING-H2 motif in mouse development

As part of a cloning strategy to identify genes involved in early mouse liver development we have isolated Praja1, a gene with similar sequences to the Drosophila melanogaster gene goliath (gl) which is involved in the fate of mesodermal cells ultimately forming gut musculatures, fat body, and the heart. Praja1 is a 2.1 kb gene encoding a putative 396 amino acid ORF and includes a COOH-terminal RING-H2 domain. Using the Jackson Laboratory BSS panel, we have localized Praja1 on chromosome X at 36 cM, which may be a candidate gene for mouse sla (sex linked sideroblastic anemia), near the X inactivation center gene, Xist. Northern blot analysis demonstrated three transcripts (3.1, 2.6 and 2.1 kb) in mRNA from adult mouse tissues brain, liver, and kidney as well as in mRNA from developing mouse embryos (days 7, 11, 15 and 17 post coitus, p.c.). In vitro transcription/translation yielded a product with an Mr of 59 kD. Immunohistochemical staining of in vitro liver explant cultures using a heterologous antibody against praja1 demonstrated cytoplasmic staining of cuboidal cells that have hepatocyte morphology and organization. The presence of the RING-H2 domain, a proline-rich region at the COOH-end, and regions rich in acidic amino acids, leads to the hypothesis that the Praja1 product is possibly involved in mediating protein-protein interactions, possibly as part of a protein sorting or transport pathway. This is strengthened by the similarity of Praja1 to rat Neurodap1, whose product has been shown to localize to the endoplasmic reticulum and golgi in brain.

The cAMP analog 8-Cl-cAMP inhibits growth and induces differentiation and apoptosis in retinoblastoma cells

Retinoblastomas appear to be derived from a multipotential stem cell of the retina, due to alterations of the Rb1 gene. These tumors arise only within a discrete time frame during childhood, prior to terminal differentiation of the retinal precursor cells. Treatment of retinoblastoma cells with certain agents can induce a partial differentiation of cell types resembling those of the mature retina, such as rod and cone photoreceptors, glia, conventional neurons and pigment epithelia. We have tested the effects of 8-Cl-cAMP, a synthetic analog of cAMP which preferentially binds to and activates the RII subunit of protein kinase A on the Y-79 retinoblastoma cell line in vitro. Y-79 cells treated with 8-Cl-cAMP produced short, branching processes and showed a substantial increase in staining for neuron-specific enolase, a marker for conventional neuronal differentiation. In contrast, dibutyryl-cAMP gives a strong increase in the glial marker glial acidic fibrillary protein. Y-79 cell proliferation was strongly inhibited by 8-Cl-cAMP at concentrations as low as 5-25 microM. 8-Cl-cAMP significantly increased the rate of apoptosis of Y-79 cells in a dose-dependent manner. It also modulated expression of the RI regulatory subunit of intracellular cAMP-dependent protein kinase A, which is produced in abnormal quantities by Y-79 cells. A decrease in protein production was observed, with no clear effect on the RI subunit mRNA expression, suggesting that RI regulation occurs post-transcriptionally.

A novel case of unilateral blepharophimosis syndrome and mental retardation associated with de novo trisomy for chromosome 3q

We have evaluated a 3 2/12 year old girl who presented with unilateral blepharophimosis, ptosis of the eyelid, and mental retardation. Additional dysmorphic features include microcephaly, high, narrow forehead, short stubby fingers, and adduction of the right first toe. Cytogenetic analysis showed an unbalanced karyotype consisting of 46,XX,add(7)(q+) that was de novo in origin. Fluorescence in situ hybridisation (FISH) using microdissected library probe pools from chromosomes 1,2,3,7, and 3q26-qter showed that the additional material on 7q was derived from the distal end of the long arm of chromosome 3. Our results indicate that the patient had an unbalanced translocation, 46,XX,der(7)t(3;7)(q26-qter;q+) which resulted in trisomy for distal 3q. All currently reported cases of BPES (blepharophimosis-ptosis-epicanthus inversus syndrome) with associated cytogenetic abnormalities show interstitial deletions or balanced translocations involving 3q22-q23 or 3p25.3. Our patient shares similar features to BPES, except for the unilateral ptosis and absence of epicanthus inversus. It is possible that our patient has a contiguous gene defect including at least one locus for a type of blepharophimosis, further suggesting that multiple loci exist for eyelid development.

[A primary study of the association of human leucocyte antigen and osteosarcoma]

OBJECTIVE

To study the association of human leucocyte antigen and osteosarcoma in Chinese Han nationality.

METHODS

The frequencies of HLA-A,B,DR,DQ locus antigens were tested in a group of 25 osteosarcoma patients and in a control group of 250 healthy persons by using complement-dependent microlymphocytoxity technique. The members of both groups were of Chinese Han nationality. Their results were compared statistically.

RESULTS

The frequency of HLA-B35 was 0.400 in patient group and 0.048 in the control group. The relative risk of suffering from osteosarcoma in persons carrying HLA-B35 was 13.220 times as high as that in those without this antigen (P < 0.01). Patients with HLA-B13 had 12.048 fold increase in relative risk with poor prognosis compared to those without this antigen (P < 0.05). A tendency of worst prognosis was seen in patients who carried both HLA-B13 and HLA-B35, but patients with HLA-B40 had 7.057 times better relative safety for good prognosis than those without that antigen (P < 0.05).

CONCLUSION

HLA-B35 is in close linkage to osteosarcoma susceptible gene in Chinese Han nationality. HLA-B13 and HLA-B40 may be separately related to the malignant and resistant genes of osteosarcoma.

[Isolation of band-specific (CA)n microsatellites from human chromosome 8q24.1]

Fourty eight recombinant plasmids containing CA repeats were isolated from human chromosome 8q24.1 band-specific pUC19 library. Among them, inserted DNA fragments from 12 plasmids were sequenced, and one new highly polymorphic (CA)n microsatellite was obtained (coding: D8S7F). It contained 11 alleles. The estimated heterozygosity reached 0.84 and 0.83 among Chinese Han Nationality people and American Anglo-Saxons respectively. It was assigned to chromosome 8 by using a human-rodent hybrid cell panel.

[Expression of T3 receptor genes in peripheral lymphocytes from patients with thyroid dysfunction]

In order to explore the expression and regulation of T3 receptor genes, the relative amount of peripheral lymphocytes c-erbA alpha and c-erbA beta mRNA from patients with Graves disease and Hashimoto thyroiditis with hypothyroidism (HTH) was determined with hybridization by using human c-erbA alpha and c-erbA beta probes. The results showed that there were two types of c-erbA alpha mRNA (6.0 kb, 3.2 kb) and three types of c-erbA beta mRNA (5.0 kb, 3.0 kb, 2.0 kb). The levels of c-erbA alpha and c-erbA beta mRNA were found to increase in HTH patients, but unaltered in Graves disease patients. This result suggests the presence of up-regulation of nuclear T3 receptor at the gene level in the lymphocytes of hypothyroid patients. The high level of c-erbA alpha and c-erbA beta mRNA may contribute in part to the increase in T3 receptor.

Effect of osteoblast supernatants on cancer cell migration and invasion

Malignant tumor cells of different origin seem to have preferential sites for metastasis. Breast cancer, prostate cancer and certain melanomas have bone as one of their preferential targets for metastasis. Bone is continuously being remodelled, a process largely controlled by local growth factors. A possible explanation for malignant cell recruitment to bone is that osteoblast products, directly secreted or released from the matrix by osteoclast resorbing activity, are able to stimulate cancer cell migration. To test this hypothesis we have utilized an in vitro system of differentiating osteoblasts which in culture progress all the way to the formation of mineralized nodules. Conditioned media obtained from these osteoblast cultures at different stages were able to induce chemotactic migration and invasion of both melanoma and breast cancer cells. The migratory and invasive phenotype was accompanied by enhanced gelatinolytic activity of osteoblast stimulated cancer cells. Our data suggest that osteoblasts secrete potent factors able to direct tumor cell migration towards remodelling bone.

Screening for grain polyphenol variants from high-tannin sorghum somaclones

Several hundred somaclones established from plants regenerated from embryogenic callus cultures of six high tannin sorghum lines were screened for variants with altered levels of polyphenols in the grain. Grain from over 6000 plants including the R 1 (primary), R2, and R3 generations were analyzed for total phenols, flavan-4-ols, and proanthocyanidins (condensed tannins). Although many variants which had lost the ability to synthesize chlorophyll were found, none of the somaclones tested had lost or greatly reduced the ability to synthesize any of the polyphenols assayed. However, we did observe statistically significant differences in polyphenol concentration between tissue culture-derived R1 plants and the parental controls. In the R2 generation the proportion of somaclones which differed significantly from the parents varied from 47% to 68% depending upon genotype. The average somaclonal variation rate and somaclonal variant frequency estimated in the tested population for the three polyphenol characteristics ranged from 37.3% to 40.7% and 5.3% to 7.8%, respectively. Variants with decreased levels of polyphenols were usually epigenetic and reverted back to normal levels in subsequent generations, but those with increased levels usually persisted after two meiotic cycles, indicating they are heritable. Variants with polyphenol levels increased up to 80% or decreased by 30% were selected for in the R3 generation.

Development and maturation of surghum seeds on detached panicles grown in vitro

A procedure for culturing detached panicles of sorghum, Sorghum bicolor (L.) Moench, was developed to achieve flowering, fertilization, and subsequent seed development and maturation in vitro. Sixteen sorghum genotypes (five high and eleven low in tannin) were tested for their ability to develop normally in culture. Panicles collected one to two days before the initiation of anthesis were cultured in flasks containing liquid medium. Contamination and medium darkening were the major obstacles encountered. Up to 55% of the panicles cultured reached physiological maturity in vitro. The frequency of seed set ranged from 30 to 97% depending upon genotype and medium. Seed and glume color were normal. Seed produced in vitro resembled those grown in vivo and germinated well, but were smaller than normal (100 kernel weight reached 50 to 70% of the control). Grain polyphenols were synthesized in the cultured panicles. Seed of high tannin genotypes produced in vitro were lower in total phenols and tannins and higher in flavan-4-ols and the 3-deoxyanthocyanidin pigments than control seed. This technique can be used for harvesting late-maturing stocks and for various sorghum studies.

Anisotropic velocity-dependent vortex forces: two-level atoms in two-dimensional standing waves

We consider the velocity-dependent light pressure force on a two-level atom interacting with a two-dimensional nearly resonant standing-wave light field. We show that there can be anisotropic cooling-heating forces that will cool the atoms along one field axis while heating them along the perpendicular axis. The force is identified as a spontaneous vortex force associated with the local traveling-wave character of the two-dimensional field. We provide a simple interpretation of this anomalous force in terms of the interplay between the vortical momentum flow of the light field and a motion-induced population transfer between the ground and excited atomic states.

[Blood rheology and cognitive function in elderly patients with uncomplicated isolated systolic hypertension]

The relationship among blood pressure, blood rheology and cognitive function were evaluated in 40 elderly patients with isolated systolic hypertension (ISH) by control-case study. The cognitive function was lower in the patient group than in the control group (79.92 + 17.05 vs 91.24 + 14.06, P < 0.01). Among the hypertensive patients, the weak correlations were observed between the cognitive function and systolic blood pressure (r = -0.11, P < 0.05), but the correlations were strengthened when the two groups were considered together (r = -0.44, P < 0.01). Blood viscosity at low shear rate and plasma viscosity in the patient group were greater than in the control group (P < 0.05, P < 0.01). A close relation existed between blood viscosity at low shear rate and cognitive function (r = -0.82, P < 0.01), whereas the patients with normal cognitive function had viscosity similar to that in control subjects (r = -0.20, P < 0.05). Thus, increased blood viscosity may be a determinant or a response to decrease cognitive function in the elderly patients with uncomplicated systolic hypertension.

[The effects of nitrendipine on the quality of life in the elderly patients with isolated systolic hypertension (ISH)]

By case-control study, we investigated the effects of nitrendipine on the quality of life in 100 patients who were participating in Chinese Trial of randomized double-blind systolic hypertension in the elderly. The results showed that the patients group had lower scores of quality of life than the matched normotensives (P < 0.05-P < 0.01). After 40-week treatment period, the active treatment group (45 patients) had satisfied blood-pressure control and improved physical symptoms. As compared with the active group, however, the control group (42 patients) scored significantly higher on physical symptoms (P < 0.05-P < 0.01), fewer on memory, vatality, vision, well-being and social activity (P < 0.05-P < 0.01). Our findings show that nitrendipine had some positive effects on the quality of life in the elderly patients with isolated systolic hypertension (ISH) and these can be meaningfully assessed with available psychosocial measures.

Somaclonal variation in high tannin sorghums

Genetic variants were found among over 6,000 primary plants (R1) regenerated from embryogenic tissue cultures of eight high tannin sorghums [Sorghum bicolor (L.) Moench]. Field assessment of somaclonal variation has progressed to the R2 population, with over 48,000 R2 seedlings (27,000 plants) in 1,126 rows from 1,055 R1 plants. A total of 43 variant phenotypes was recovered, including several types of chlorophyll deficiencies, dwarfism, short culm, sterility, narrow leaf, and several previously unreported variants, such as ragged leaf, multibranched heads, and Hydra, a developmental variant which produces large numbers of panicles. Variation production greatly depends on parent genotype and appears to increase with increasing time in cultures. The toal average somaclonal variation rate (based per 100 R1 plants) and somaclonal variant frequency (based per 100 R2 plants) estimated in the tested population were 11.3 and 1.6, respectively. Chimerism was found in regenerants. The estimated size of the mutated sector carried by mutant regenerants ranged from the whole plant to less than 3% of a single head. The average proportion of mutated R1 heads carrying large (80%-100%), medium (40%-80%), and small (<40%) mutated sectors was 38.7%, 26.0% and 35.3%, respectively. Some sector mutations do not appear until the R3 generation. In order to avoid losing variants, the population for selecting somaclonal variation should be as large as possible. Some of these variants found may be useful for further study or for use in breeding programs.